Peel the potatoes and cut them into Pont Neuf size potatoes – 1 cm thick by 7 cm long.
Wash the chips under cold running water to rinse off any free starch.
Drain and dry the chips well and place them in small batches in a chip basket.
Heat the oil in a pan to 120º– 130ºC/250ºF. Ideally the pan should be 25–30 cm (10–12") high and 25 cm (10") round. The oil should fill 2/3rds of the pan.
Lower the basket of chips into the oil and fry for 7–8 minutes, until soft but not brown. Shake the basket occasionally to ensure even cooking.
Lift the basket out of the pan and drain the chips on absorbent kitchen paper.
Heat the oil to 175ºC/347ºF and return the chips to the oil for 2–3 minutes until brown.
Preheat the oven to 175ºC/347ºF/Gas mark 4.
Place the whole garlic bulb on a baking tray in the oven for approximately 45 minutes until soft.
Remove from the oven and peel each clove, putting them through a sieve to produce a roasted garlic paste. You can use a fork or a food processor if you wish.
Add 5–6 cloves of garlic paste to the mayonnaise and stir in. You may wish to add more if you love garlic. The remaining garlic paste can be stored by putting it into an ice cube tray and freezing until a later date.